1. Field of the Invention
The present invention is related to communication systems and methods. More particularly, the present invention relates to fast fourier transform (FFT) architecture in a multi-mode wireless processing system.
2. Description of the Related Art
This section is intended to provide a background or context. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
Wireless devices continue to need the capability to handle increasingly high data rates. To accommodate multimedia content, for example, data rates for wireless devices may need to match broadband rates for hard-wired devices. Wireless device users increasingly demand multifunction, multi-technology devices to obtain different types of content and services via multiple wireless networking technologies.
Many attempts have been made to build broadband capability into small, handheld devices. For example, wireless data technology commonly known as Wi-Fi 802.11 provides high-speed capability to handle such demanding applications as high quality (high definition) streaming video and image content. However, conventional 802.11 implementations fail to meet user-acceptable power consumption parameters. Even the lowest power-consuming 802.11 implementations currently available severely limit “talk time” (active state during which voice, data, or video is being transferred) for battery operated devices.
Beyond devising an 802.11 implementation with acceptable power consumption, another challenge is to establish a wireless implementation that supports two or more networking modes of operation, such as 802.11, Bluetooth, Ultra Wideband (UWB), WiMax (802.16d and 802.16e), 802.20, and 3G and 4G cellular systems. Wireless devices need to be able to offer a variety of wireless networking technologies. The ability to operate according to multiple networking standards and technologies in a single device is referred to as “multi-mode” capability.
Most conventional mobile devices are either digital signal processor (DSP)-based, application specific integrated circuit (ASIC)-based, or an ASIC/DSP hybrid architecture. Several engineering considerations, such as power efficiency, design flexibility and cost, prevent either approach from being suitable for broadband wireless. Because of architectural limitations, conventional approaches may be able to provide high data rates, but only at the expense of power consumption, resulting in an unacceptably short battery life.
With new wireless standards being introduced everyday, traditional ASIC design is too inflexible to continually accommodate these rapidly evolving standards. Once the integrated circuit design cycle begins for a new standard, modifications that inevitably occur necessitate re-starting from scratch or re-spinning the ASIC chip. To provide the multiple wireless capabilities end users demand on a single device, ASIC and DSP approaches support multi-mode capability by simply stacking additional “processing circuitry” in parallel, significantly increasing device volume and manufacturer costs for each new mode.
There is a need for a communication system and architecture that provides for multi-mode communication with broadband performance and low power consumption. There is also a need for performing fast fourier transforms (FFTs) in a manner that minimizes power consumption. Further, there is a need to provide wireless communication devices that can function across multiple networks and multiple communication standards. Even further, there is a need to reduce baseband circuitry and improve ASIC algorithms to achieve ultra low power/cost advantage, resulting in performance processing gains and reductions in power consumption, gate count and silicon cost.